爆炸冲击作用下埋地并行输气管道的动力响应

天然气泄漏爆炸已成为埋地输气管道主要的极端灾害。选取TNT当量法作为输气管道小孔泄漏致爆的估算模型,适当选取材料本构模型,采用任意拉格朗日-欧拉方法(ALE),在验证模型精度的基础上,建立了埋地输气管道-土壤-炸药耦合的三维实体模型,分析了埋地输气管道动力响应(等效应力、位移)与爆心距和炸药量之间的关系。研究结果表明:ALE法可较好地描述球形爆炸波在土中的传播规律,且可形象展示爆炸空腔及地表土丘的宏观演化过程;在爆心距为205 cm时,应力随着药量的增大而增大,管体的抗爆极限药量为58.4 kg;应力与位移均随着装药量的增大或爆心距的减小而增大;X向位移、迎爆点及背爆点的Y向位移随着时间的变化先增大后减小,管顶的Y向位移则呈现先增大后减小的二次震荡,管底的位移近似呈正弦规律变化;基于应变的失效判据与应力的失效判据评定结果存在偏差,应力评定结果相对偏保守。所得结论可为并行输气管道的安全评估提供参考。

Dynamic Response of Buried Parallel Gas Pipeline Under the Explosion Impact

Natural gas leakage and explosion have become the main extreme disasters of buried gas pipelines.TNT equivalent method is selected as the estimation model for small hole leakage explosion of gas pipeline.The material constitutive model is appropriately selected.Arbitrary Lagrange-Euler method(ALE)is used to verify the accuracy of the model.A three-dimensional solid model of buried gas pipeline-soil-explosive coupling is established.The relationship between dynamic response(equivalent stress,displacement)of buried gas pipeline and explosion center distance and explosive quantity is analyzed.The results show that the ALE method can well describe the propagation law of spherical explosion waves in the soil,and can visually show the macro-evolution process of the explosion cavity and the surface mound.Under the explosion center distance of 205 cm,the stress increases with the explosive charge.The anti-explosion limit charge of the pipe body is 58.4 kg.Both the stress and displacement increase with the explosive charge or the decrease of the explosion center distance.The X-direction displacement,the Y-direction displacement of front explosion point and rear explosion point increases first and then decreases with time.The Y-direction displacement of the top of the pipe presents a second shock that increases first and then decreases.The displacement of the bottom of the pipe changes approximately sinusoidally.There is a deviation between the strain-based and stress-based failure evaluation results.The strain-based results are relatively conservative.The study can provide a reference for the safety assessment of parallel gas pipelines.